Switching device



Filed June l5, 1956 MM5/Vrai /VraRA/fy Patented June 29, 1937 UNITED STATES SWITCHING DEVICE Frans lands, assignor to N.

Hendrik de Jong,

Eindhoven, Nether- V. Philips Gloeilampenfabrieken, Eindhoven, Netherlands Application June 15,

1936, Serial N0. 85,372

In Germany July 5, 1935 7 Claims.

My invention relates to switching devices, and more particularly to switching devices for controlling a plurality of circuits in time sequence.

My invention is particularly adapted for con- 5 trolling the cathode heating circuit and d. c. load circuit of gas-filled rectiers, and I shall describe same in this connection, although its use is not limited thereto.

To prevent premature loading of the cathode l of a gas-lled rectier with emission current, it is desirable, and in many cases imperative, that the anode voltage be not applied until the cathode has been heated to a certain predetermined temperature. For this purpose, numerous l switching devices have been proposed which in general operate according to two methods. The rst method merely uses a manual switch for the cathode heating current and a manual switch for the d. c. load circuit; whereas the second method uses a manual switch for the cathode heating circuit, and a time-delay device which automatically closes the d. c. circuit after a predetermined time interval.

Such switching devices however, have the disadvantages that they either do not provide the proper protection or are large, expensive, and complicated. For instance, when merely using two manually-operated switches, the possibility always exists that the operator might prematurely close the direct current switch and thus apply the anode voltage before the cathode has reached its proper temperature. Although the automatic devices operating according to the second method prevent any errors due to the human element, such devices are expensive and complicated, due to the fact that an automatic time-delay, as well as one or more auxiliary relays or contactors must be provided for each rectiiier.

The object of my invention is to eliminate the above disadvantages and to provide for this purpose a semi-automatic switching device which is of inexpensive and simple construction, and which completely protects the rectifier from premature application of the anode voltage.

In accordance with the invention, I provide manual switches to control the a. c. and the d. c. circuits, and mechanically interlock these switches in such a manner that the d. c. switch cannot be closed within a predetermined time after the a. c. switch has been closed, and that the a. c. switch cannot be opened until after the d. c. switch has been opened.

More particularly, I provide an electricallyactuated mechanical interlock between the two 55 switches, and control the movement of this interlock by a time-delay device, preferably of the bimetallic type, whereby, at a predetermined time interval after closure of the a. c. switch, the d. c. switch is unlocked and the a. c. switch is locked in its closed position. As an interlock I prefer to use a locking member so arranged between cooperating members of the a. c. and d. c. switches that the a. c. switch is locked in its closed position when the direct current switch is in its closed position, and the d. c. switch is locked in its open position when the a. c. switch is open.

I prefer to use manual switches of the rotarytype as this allows the interlocking to be eiected in a very simple manner by means of a slidable rod-shaped locking member cooperating with indentations in rotatable members of the switches and moved by an electromagnet into that position in which the direct current switch is unlocked.

In order that my invention may be clearly understood and readily carried into effect, I shall describe same more fully with reference to the accompanying drawing, in which:

Figure l is a schematic view partly in perspective of a switching device according to the invention, and

Figure 2 is a perspective View of a device according to the invention.

The switching device shown in Figure l is used for controlling the a. c. and d. c. circuits of a single-phase gas-filled rectifier 30, and comprises an a. c. rotary manual switch B, a d. c. rotary manual switch C, a time-delay device A, and an electrically-actuated mechanical interlock D.

The switch B comprises a manually-operated shaft upon which are secured a commutator 4t, and a rotatable disc-shaped member I provided on its periphery with two diametricallyopposite indentations 43. The commutator 46 comprises a cylinder of insulating material provided with two conductive segments 34 adapted to shunt stationary contact fingers 35i-31, and Contact fingers 38-39 respectively.

The switch C is similar in construction to the switch B, and comprises a manually-operated shaft 5l carrying a rotatable member 2 having two diametrically-opposite grooves 4, and a commutator 48 of insulating material provided with two conductive segments 35 adapted to shunt stationary contact iingers 4t and 4l.

Slidably supported between members l and 2 and movable in the plane thereof so that its ends can enter the grooves 43 and 4 respectively is a rod-Shaped member 3 having a portion 60 of magnetic material and carrying a movable contact I6, which in the position shown cooperates with a stationary contact 5I. Surrounding the rod 3 to the left of the portion 60 is a solenoid coil 5, which serves to move the rod in the direction of the arrow.

A source of alternating current to be rectified is connected across terminals I0 and II, connected to contact ngers 36 and 39 respectively of switch B. Contact 37 is connected to one terminal oi the primary winding of a cathode heating transformer 3I, whose other end is connected to the contact 38 whereby switch B controls the heating of the cathode 62 of tube 30.

The anode 63 of rectier 30 is connected through a d. c. load 44 to contact nger 4I; contact iinger 48 being connected to terminal I0. Thus switch C controls the d. c. circuit of the tube.

The time-delay device A, which is of the thermal type, comprises a stationary contact I9 having a terminal 22, and a bimetallic strip 58 carrying a movable contact I8 and surrounded by a heating coil 6I. Coil 6I has one end connected through a current-limiting resistance I'I to the contact 5 I, and its other end connected to contact I8 at 24 and to iinger 3I of switch B. Thus, energization of coil 6I is controlled by contacts I6-5I and by iingers 38-38 and 36-31 of switch B.

With the device in its off-position as shown, the right hand end of rod 3 extends into the groove 4 to thereby prevent movement of shaft 41 and closure of the d. c. circuit whereas switch `B is unlocked. To place the device in operation,

shaft is rotated clockwise or counterclockwise though an angle of 90 whereby segments 34 shunt ngers 36-31 and fingers 38--39 respectively, to thereby energize transformer 3| and initiate heating of the cathode 62.

At the same time coil vIFI is energized through a circuit including terminal l0, iingers 158-39, conductor 53, contacts I6 and 5I, resistance II, coil 6I and back through fingers 36-31 to terminal I0. After a predetermined time interval, depending upon adjustment of the time device A, contact I8 touches contact I9 and closes the circuit of coil 5, which circuit may be traced from contact ringer 38, through coil 5, conductor 50, contacts I9 and I8, point 24 and back to contact finger 31. Energization of coil 5 moves rod 3 in the direction of the arrow, whereby its left-hand end enters the indentation 43 (indicated by dotted lines), and its right-hand end leaves the groove 4 to unlock switch C. At the same time the energizing circuit of coil 6I is interrupted by the breaking of contacts I6 and 5I, whereby the bmetallic strip 58 is allowed to cool, contacts I8 and I9 break, and coil 5 is deenergized.

Switch C, being unlocked, can now be rotated through 90 whereby one of the Contact segments 35 bridges contact iingers 40 and 4I to close the d. c. circuit. Upon rotating switch C' from the position shown, the peripheral surface of member 2 cooperates with the right hand end of rod 3 to prevent its movement to the right and thus switch B is locked in its closed position.

To place the device out of service, switch C is first returned to the position shown, thereby interrupting the d. c. circuit, and bringing one of the grooves 4 into alignment with the righthand end of rod 3. Switch B may then be re turned to the position shown whereby the a. c.

5 circuit is interrupted, rod 3 is moved tQ the right,

and the device assumes the position shown in the iigure.

The construction of a device according to the invention is illustrated in Fig. 2, in which parts corresponding to those oi Fig. 1 are given the same reference numerals. The device shown in Fig. 2 comprises a sheet metal frame 'I0 upon which are mounted the various parts of the device. The switches A and B of Fig. 1 are only partly shown and are indicated by their shafts a coil 5, and an armature formed of two bundles of laminations 21 and 28 secured to the rod 3. The locking rod 3 passes through the space formed between the two bundles 25 and 26 and carries the contact I6 which cooperates with the Contact 5I insulatingly mounted on the frame l0.

Upon energization of coil 5, and with shaft 45 rotated 90 from the position shown, the mov-- able armature 2'I-28 is attracted by the core 25-26 in the direction of the arrow, whereby locking member 3 is moved into its left-hand position and the auxiliary contact I6 is opened. In this position, as stated above, it is possible to turn the shaft 2 into the closed position of switch C.

Mounted on the top of the container is the current limiting resistance Il and the bimetallic relay A. As shown, the relay A is mounted within a glass envelope provided with a base which is inserted in a standard socket, however it may be of various other types and constructions which are well known in the art.

While I have described my invention in connection with specific examples and appiications, I do not wish to be limited thereto, but desire the appended claims to be construed as broadly es permissible in View of the prior art.

What I claim is:

l. A switching device for controlling two circuits comprising a manually-operated switch for controlling one circuit, a second manually-operf ated switch for controlling the second circuit, and means to make said rst switch operative after a predetermined time interval after closure of said second switch and to prevent opening of said second switch while said first switch is closed, said means comprising a movable interlocking member cooperating with said switches to mechanically lock same, electromagnetic means for moving said member to unlock said rst switch, and means including a time-delay device to energize said electromagnetic means at a predetermined time after closure of said second switch.

2. A switching device for controlling two circuits comprising a manually-operated switch for controlling one circuit, a second manually-operated switch for controlling the second circuit, and means to make said first switch operative after a predetermined time interval after closure of said second switch and to prevent opening of said second switch while said rst switch is closed, said means comprising a movable interlocking member cooperating with said switches to mechanically lock same, electromagnetic means for moving said member to unlock said iirst switch, and means including a thermal time-delay relay to energize said electromagnetic means at a predetermined time after closure of said second Switch.

3. A switching device for controlling two circuits comprising a manually-operated switch for controlling one circuit, a second manually-operated switch for controlling the second circuit, and means to make said first switch operative after a predetermined time interval after closure of said second switch and to prevent opening of said second switch while said first switch is closed, said means comprising, a movable interlocking member cooperating with said switches tol mechanically lock same, and electromagnetic means including a bimetallic time-delay device to energize said electromagnetic means at a predetermined time after closure of said second switch.

4. A switching device for controlling two circuits comprising a manually-operated rotary switch for controlling one circuit, a second manually-operated rotary switch for controlling the second circuit, and means to make said first switch operative after a predetermined time interval after closure of said second switch and to prevent opening of said second switch while said rst switch is closed, said means comprising operating members rotatable with said switches and provided with locking indentations, a rodshaped interlocking member cooperating with said indentations to mechanically lock said switches, electromagnetic means for moving said member to unlock said first switch, and means including a time-delay device to energize said electromagnetic means at a predetermined time after closure of said second switch.

5. A switching device for closing the anode circuit of an incandescible cathode rectier at a predetermined time after closure of the cathode heating circuit comprising a manually-operated switch for controlling the anode circuit, a second manually-operated switch for controlling the cathode heating circuit, and means to make said first switch operative after a predetermined time after closure of said second switch and to prevent opening of said second switch while said rst switch is closed, said means comprising a movable interlocking member cooperating with said switches to mechanically lock same,

electromagnetic means for moving said member to unlock said first switch, and means including a time-delay device to energize said electromagnetic means at a predetermined time after closure of said second switch.

6. A switching device for closing the anode circuit of an incandescible cathode rectier at a predetermined interval after closure of the cathode heating circuit comprising a manuallyoperated rotary switch for controlling the anode circuit, a second manually-operated rotary switch for controlling the cathode heating circuit, and means to make said rst switch operative after a predetermined time interval after closure of said second switch and to prevent opening of said second switch while said rst switch is closed, said means comprising operating members rotatable with said switches and provided with locking indentations, a movable interlocking member cooperating with said indentations to mechanically lock said switch, electromagnetic means for moving said interlocking member to unlock said rst switch, and means including a thermal time-delay relay to energize said electromagnetic means at a predetermined time after closure of said second switch.

7. In combination, a gas-filled rectier tube having an incandescible cathode and an anode, and a switching device for preventing application of the anode voltage before the cathode has been heated to a predetermined temperature, said device comprising a manually-operated switch for controlling the anode voltage, a second manually-operated switch for controlling the heating of the cathode, and means to make said rst switch operative after a predetermined time interval after closure of said second switch and to prevent opening of said second switch while said rst switch is closed, said means comprising a movable interlocking member cooperating with said switches to mechanically lock same, electromagnetic means for moving said member to unlock said first switch, and means including a time-delay device controlled by said second switch to energize said electromagnetic means at a predetermined time after closure of said second switch.

FRANS HENDRIK DE JONG. 

